At present, televisions (TV) commonly use function keys. In addition to the most basic TV power on/off key, they usually include channel switching keys, menu keys, and up, down, left and right directional keys, etc. The purpose is to be able to operate the TV with basic functions such as TV on and off, channel switching, and menu option operation when the TV remote control is unavailable. In order to let the TV user know the function of each key, the current technology is mostly to print the function icon corresponding to the key on the TV shell, next to the position where each key is located, or on a sticker that is then pasted next to the key.
The main problem with the existing method is that the printed icon is difficult to modify. In case the icon is misplaced at a position not corresponding to the key, the user cannot operate the function key properly.